phosphines

https://doi.org/10.1351/goldbook.P04553
PH3 and compounds derived from it by substituting one, two or three hydrogen atoms by hydrocarbyl groups R3P . RPH2 , R2PH and R3P (RH) are called primary, secondary and tertiary phosphines, respectively. A specific phosphine is preferably named as a substituted phosphane, e.g. CH3PH2 methylphosphane.
See:
phosphanes
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1357 [Terms] [Paper]